Influence of the electronic distribution of polymers in the spatial conformation of polymer grafted carbon nanotube composites

In this work we report the covalent functionalization of multiwalled carbon nanotubes (MWCNTs) with polyacrylonitrile (PAN) and polyvinylpyridine (PVP) by the graft from method. Differences in the electronic distribution of both polymers resulted in different interaction between polymers and the nanotubes. It was found that PVP chains wrapped the nanotubes while nanotubes functionalized with PAN presented PAN chains forming amorphous entanglements on the nanoscale linked to the MWCNTs. Differences in the conformation between both polymers and the MWCNTs can be attributed to interactions between the aromatic groups in PVP and the MWCNTs through π-π stacking. The absence of aromatic groups in the case of the PAN chains favours the interaction between them. The functionalization efficiency was characterized using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and UV-vis spectroscopy, while morphological changes were characterized by high resolution transmission electron microscopy.